DE7240976U - Sheet extruder - Google Patents

Description

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DIpI.-Phye. Eduard BetzUr rmmmtm-.mmm a. »« ⁵¹⁰¹⁴ Dlpl.-lng. W. Herrmann-Trentepohl "»

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Dresdner Bank AQ Herne 7- «049β Postal checking account Dortmund I

Ref .: MO 3813 B / hr

Please indicate in the answer

Pick-up box

PONT-A-MOUSSON S.A., 91, avenue de la Liberation, 54 Nancy (France)

Sheet extruder

The innovation relates to a sheet extruder for plasticizing and extruding plastic or elastomeric material, especially solid polyvinyl chloride, Polyethylene, polystyrene, polypropylene and polycarbonates.

Extruders are already known which have a fixed, smooth plate (stator) opposite one another. and a circumferential plate with spiral ribs (Rotor), which is the plastic material that at the end is fed and is subjected to a shear force between the rotor and the stator, in the direction of

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promote a central discharge opening. In these extruders occurs to the entrainment by the spiral ribs one Pumping effect through the so-called Weisenberg effect as a result of the relative movement of the oppositely arranged Plates added.

There are also known extruders with completely smooth plates, in which the Weisenberg effect alone moves the plastic material towards the center when the rotor is opposite the stator rotates.

The Weissnbsrg = Effect is too weak for you alone, in order to ensure a sufficient throughput of plastic material in industrial use.

An extruder has therefore already been developed whose plates are roughened on the opposing surfaces are so that the material is entrained and a shear force is exerted on the plastic cake that is in the gap is compressed between the plates. In this way, a greater throughput of plastic material was achieved.

Since the Weisenberg effect is not sufficient to achieve, among other things, a usable discharge pressure of the plastic material, an axially arranged, short discharge screw connected for the plastic material.

The Dttiiehfr obtained in the last two cases Seats and pressures, however, were not optimal.

The innovation is based on the task of a sheet extruder to create that has a larger and much more uniform throughput.

This task is performed in an extruder with two oppositely arranged plates, one of which stationary and the other is rotatably mounted, according to the invention achieved in that on the one plate on the other plate opposite side ribs 4n in the form of spiral sections are provided, which passages between them with width dimensions larger than the width dimensions the ripper form which along their entire length

by at least a quarter of the gap width at the relevant Point upwards.

According to a particular embodiment, the extension has the fixed plate has ribs which are identical to those in terms of length, width and direction of curvature the other plate, the height of the ribs being less than half the gap width.

Further features and advantages of the innovation are based on explained in more detail by embodiments reproduced in the drawing. Show it:

Mg. 1 schematically shows an axial section of a first embodiment ;

Pig. 2 is a plan view of the embodiment of FIG. 1 according to the section 2-2 in Figure 1;

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Pig. 3 is a perspective view of the taken along the plane of union its housing open extruder;

Pig. 4 schematically shows an axial section through a second exemplary embodiment;

Fig. 5 is a bottom view of the embodiment of Fig. \ according to the section along line 5-5.

The extruder according to FIGS. 1 to 3 consists of a cylindrical housing with a horizontal axis XX, which is formed by a circular base plate 1 and a cover 2 designed as a cylindrical shell, the base plate 1 forming a stationary plate or the stator. A feed hopper 3 for material to be extruded, for example solid polyvinyl chloride, opens into the cylindrical wall. The axis of the stator could also be arranged vertically, in which case the funnel is replaced, for example, by a feed screw. The stator 1 has a cylindrical bore 4 which is central to the axis XX and which is used to discharge the extruded material. Opposite the stator 1, a circular plate, the so-called rotor, rotates coaxially with it inside the housing. This is driven by a drive shaft 6, the axis of which runs in the direction XX. On the side opposite the drive shaft 6, the rotor 5 is extended by a short discharge screw 7, the axis of which is also in the direction XX . Its diameter corresponds to that of the bore 4 in which it is arranged.

724Ö976-U.73

The stator 1 and the rotor 5 point to their opposite one another End faces ribs or blades (in the exemplary embodiment six on the stator and five on the rotor), labeled 8 and 9, respectively. They form sections a logarithmic spiral and are guided around the center of the plates, i.e. around the bore 4 for the stator and around the Auger 7 for the rotor.

The dimensions of the ribs 8 and 9 and their sense of direction of the plate in question are identical, so that they cross, since the plates 4 and 5 are arranged opposite one another. Her Length is dimensioned such that, viewed from the axis X-X, they enclose a central angle of approximately 90 °. Your middle one Kr-üüffircmg corresponds roughly to that of one on the X-X axis centered circle, which is guided approximately through its center, its curvature is such that the respective Rotational movement leads to a centripetal entrainment of the plastic material. The end of the ribs adjacent to the X-X axis lies on a circle at a sufficient distance from the channel 4 or the screw 7, so that a smooth circular ring is enclosed by them which is about half the width of the one that covers the ribs. The other end of these ribs is arranged on a circle, starting from the fixed plate as a frustoconical Surface 10 is formed and is slightly inclined in the direction opposite to the rotor 5. The purpose is given below explained.

The ribs 8 and 9 protrude on the plates by a height h; it is smaller than half the width 1 of the gap 11 separating the plates (in the exemplary embodiment approximately a Third of this width), but larger than a quarter, whereby

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this height is constant over the entire length of the ribs. The ribs 8 and 9 form with one another in the gap 11 in the area their interfaces 12 (Pig. 2) from a space of small axial extent.

Its width is of the same order of magnitude as its height. The ribs 8 and 9 limit due to their small number and their narrow width, wide passages 13 and 14. These passages 13 and 14 open at one end in FIG Direction to the plate edges and at the other end to the discharge channel 4 and the discharge screw 7 out.

In the area of its edge parallel to the axis XX, the rotor 4 has blades, wings or hooks 15 (five in the exemplary embodiment) of elongated shape, which are arranged in the direction of a spiral and whose profile extends beyond that of the ribs 9. They are wider than the ribs 5 'but are sufficiently spaced from one another so that there is a passage between them in the extension of the passages 14 which separate these ribs 9. These blades 15 'of width 1 corresponds to the above on the r rotor length of the gap 11, which is limited at this point of the frustoconical surface 10, move through a smooth ümfangskammer for the supply of material into which the hopper 3 flows.

The per se known heating and cooling devices of the stator 1 and the rotor 5 are not shown.

The extruder described works as follows:

With the rotor 5 rotating, the plastic material to be extruded is for example solid polyvinyl chloride granular or as

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7740976-U.73

Powder fed through the funnel 3 and then passed through the blades 15 into the gap 11 and through the ribs 9 of the rotor taken.

The material softened by frictional heat becomes progressive plasticized as it moves from the periphery to the center and takes the form of a flat one Cake that sticks to plates 1 and 5 and fills aisles 13 and H on the plates.

On the stator 1, this plastic cake tends to form a unit with the stator as a result of the ribs 8. On the rotor 5 it tends to be entrained by rotation as a result of the ribs 9. Between the two, and especially in that axial narrow space or gap between the ribs 8 and 9, this cake is a considerable shear force in its mass exposed. In addition, the juxtaposed ribs of the rotor 5 and the ribs 8 of the stator cause an inevitable centripetal pumping of the plastic material, that is, its transport towards the center, in particular at the crossing points 12 of the ribs 8 and 9 in the entire gap 11, since these crossing points in the direction of the center accordingly the radial pillar f the pig. 2 converge. The greatest shear force and consequently the greatest heat generation occurs in the central plane of the gap 11, since the ribs 8 and 9 have an identical height. Starting from this central plane results There is a symmetry of the heat transport and the temperature distribution and thereby a stable operation, i.e. a regular one Throughput that has never been achieved before. The throughput of plastic material through the discharge bore 4 becomes considerably increased.

The comparison values of two known extruders, one designated with A and with smooth plates, the other with B. and with roughened plates, and an extruder C according to the invention, the plates of which have spiral ribs, when extruding solid powdered polyvinyl chloride through an annular discharge bore 4 of an inner diameter of 20 mm (diameter of the screw 7) and of one. outer diameter of 28 mm are as follows:

Speed of the rotor throughput in revolutions / min in kg / h

Remarks

Extruder A

100

uneven throughput

Extruder B

not so erratic throughput

Extruder C

Rib height h between 3 and 5 mm - gap width 1 10 mm

very even throughput

100

very even throughput

Apart from the larger and more uniform throughput, the same temperature arises for the plates 1 and 5 as a result of the an existing plane of symmetry in which the heat is mainly is generated, while in the known extruder A with smooth plates and the known extruder B with roughened plates of the The stator heats up considerably higher than the rotor and consequently always has to be cooled.

The embodiment of FIGS. 4 and 5 differs from the previous one by the changed zone for the feed (Edge zone of the plates).

The extruder according to FIGS. 4 and 5, whose parts identical to those of FIGS. 1-3 have the same reference numerals with an appended a, is fed with each plastic material to be extruded not by a funnel, but by means of two radially arranged feed screws 16, which open radially into the space between the plates 11 ^{a of} the part 1 ^a - 2 ^a on the stator 5 ^a. This type of feed is advantageous because the extruder can work regardless of whether its axis YY is oriented vertically or horizontally. As in the above embodiment, the stator has an axial discharge bore 4 ^a in the direction of the axis YY and the rotor 5 ^a is extended in the direction of the axis YY by a short discharge screw 7 ^a .

The stator 5 ^a has an end face which, in a modification of the previous embodiment, is completely smooth and is provided in the peripheral zone for the feeding of the plastic material with a frustoconical part 10 ^a , which widens under a slight inclination opposite to the rotor 5 ^a . Instead of a constant width, as in the extruder of FIGS. 1-5, the

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Gap between the flats 11 ^a at the edge At the height of the bores, a maximum width into which the feed screws 16 open, then gradually decreases in the direction of the center and is then in a zone between the peripheral feed zone and the bore 4 ^a and the discharge screw 7 ^a constant. During a third of the radial extension covered approximately in Aueführungsbeispiel according to FIGS. 1 to 3, the peripheral zone of the stator, with the exception of the opening 4, here covers the zone 10 ^a over half of the same area.

The rotor 5 ^a carrying instead of the blades 15 in the peripheral ExiiSpöiBe2> üXi6 όχϋθ small number τοπ spiral önsigsn ribs 9, for example svreij of low ** B3 * ei _"t;? Defining between check wide passages 14 ^a, which at one end open into the outer zone of the interspace and at the other end into its central part. The center angle enclosed by each rib is of the order of 400 °, one being offset from the other by 190 °, and with its inner end towards the center slightly above the Border between the frustoconical shape
is.

shaped surface 10 ^{a of} the stator and its planar part out

The ribs 9 ^{a of} the plate 5 ^a have a decreasing height from the edge to the center, so that they overall ^{follow the frustoconical edge profile 10 a of} the stator, that is, the width in the space 11 ^a between the plates decreases. In other words, the ribs 9 ^a have a maximum height at the edge that deviates only slightly from the maximum width of the space 11 ^a between the plates and then decreases. This variation of the width of the gap 11 ^a between the plates and the height of the corresponding ribs 9 ^& corresponds to the compression ratio of the plastic material _f that of the fluid

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pulverized state into the compact pulverized, quasi-solid state in this peripheral feed zone transforms.

The rotor 5 ^{a of} this extruder has in its central zone 17 spiral ribs that the ribs 9 of the extruder after the Pig. 1-3 correspond and which can connect to the peripheral spiral ribs 9 ^a in the feed zone. In the diagrams deir Pig. 4 and 5 these central ribs are not shown,

Other embodiments Bind possible instead be selected horizontal, wherein two or more charging hopper 3 and / or on the edge of Rotora 5 other supply means are "for example, advance the axis direction of the plates dos üxtruders of Pig. 1-3 vertically provided as the blades 15. in the extruder according to Pig. 1-3, the or the hopper by two or more radially arranged feed screw can be replaced 16th Finally, the plates (the stator and the rotor) may be on the entire S \ rnfläche or in a portion thereof Ribs in a spiral shape.

As a modification, the central part of the plates can have various types of short ribs or guide strips.

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Claims (10)

Protection claims 1. Plate extruder with two oppositely arranged upright plates of which di3 a fixed and the other rotatable is' characterized in that the one plate (1, 5, 5 ^a) formed as sections of a spiral Rijppen (8y 9 _t 9 ^&) has, which among each other form passages (1 ^, 14, 14 ^a ), the width of which is large compared to the width of the ribs, and that the ribs protrude over their entire length by a height (h) which is at least equal to a quarter of the width (1) of the gap (11, 11 ^a ) is at the relevant point. 2. Extruder according to claim 1, characterized in that the gap (11, 11 ^a ) between the plates has an edge zone for the feed (10, 10 ^a ), and that the ribs (8, 9) at least between this zone (10, 10 ^a ) and the central discharge opening (4, 4 ^a ) are arranged, 3. Extruder according to one of claims 1 and 2, characterized in that the gap (11 ^a ) between the plates has an edge zone for the feed (10 ^a ), the ribs (9 ^a ) being arranged at least in this zone (10 ^a ) are. 4. Extruder according to one or more of claims 1-3, characterized in that the two plates (1, 5) Each with regard to their length, width and their The direction of curvature have identical ribs and their height (h) each smaller than half the gap width 1st. 5. Extruder according to claim 4, characterized in that the ribs (8, 9) of the two plates have the same height (h). - 13 - 6. Extruder according to one or more of claims 1 to 5, characterized in that at least the rotating plate (5, 5) has ribs (9, 9 ^a ). 7. Extruder according to one or more of the preceding claims 1 to 6, characterized in that when present on the rotor (5) in the peripheral feed zone Shovels (15) the ribs (8, 91 only between ...) this zone and the central discharge opening (4) are and that the blades (15) are present in the same number as the ribs (9) and extend in their extension. 8. Extruder according to claim 2 and 3, characterized in that the ribs (9 ^a ) of the edge zone lie in the extension of the ribs which are arranged between this edge zone and the central discharge opening (4 ^a ). 9. Extruder according to one or more of Claims 3 and 6 to 8, characterized in that the fixed plate has a peripheral frustoconical opposite to the .- * Direction of the rotating plate (5 ^a ) has inclined surface (10 ^a ), which is occupied only with ribs, the height of which decreases in the direction of the center of the plate. 10. Extruder according to one or more of claims 1 to 9, characterized in that the direction of the ribs (8, 9, 9 ^a ) is chosen such that the plastic material is given a Zentrxpetale movement.